1N, 1N{40 -Phenylenbis(5-methyl-4-pyrazolin-3-ones) and process for preparing same

ABSTRACT

There is disclosed a new class of pyrazolones having the formula   IN WHICH THE PYRAZOLONE RING A&#39;&#39; is in either meta or para position with respect to the pyrazolone ring A. A process for preparing the new products is also disclosed.

United States Patent Venturello Dec. 30, 1975 IN,lN-PIIENYLENBIS(S-METI-IYL-4- [56] References Cited PYRAZOLlN-S-ONES)AND PROCESS FOR UNITED TES TS PREPARING SAME 2,013,181 9 1935 Kracker etal. 260/310 A 2,936,306 5/1960 Schmid et al. 260/310 A [75] Inventor:Carlo Venturello, Turin, Italy OTHER PUBLICATIONS [73] A i M m ti i EdiS A Mik Recueil des travaux chimiques des pays-bas, tome 58,

Italy pp. 58-62 (1939).

[22] Filed: Sept. 25, 1973 Primary ExaminerDonald B. Moyer [2l] Appl.No; 400,516

[57] ABSTRACT [30] Forelgn Apphcatmn Pnonty Data There is disclosed anew class of pyrazolones having Sept. 26, 1972 Italy 29674/72 theformula T A CH3 ll A l CH c 2 NH 3 C c IL [52] US. Cl 260/310 A in whichthe pyrazolone ring A is in either meta or [5 1] Int. Cl. C07D 231/08para position with respect to the pyrazolone ring A. A [58] Field ofSearch 260/3l0 A process for preparing the new products is alsodisclosed.

3 Claims; No Drawings 1N,1N-PHENYLENBIS(SMETHYL-4 PYRAZOLIN- 3-ONES) ANDPROCESS FOR PREPARING SAME The pyrazolon es of this invention,"- whichare new compounds that have not been described in the litera pounds canbe preparedstarting from the correspond-- ing tetra-azotizedphenylendiamines obtained in the solid state, by simple reaction withthe diacetyl dimer in the aldolic form. The reaction sequence may berepresented as follows:

l-INH NH H wherein B is H80 The reaction between the phenylendiaminetetrazonium salt and the diacetyl dimer occurs only when the former isin the solid state. The choice of the l-lSO annion is due to the factthat the tetra-azotization is carried out in H 80 and that thetetrazonium salt having H80 as an anion is easily obtainable in thesolid state.

Solvents which dissolve the tetrazonium salt have a detrimental effecton the course of reaction (I), as can the environment in which thetetra-azotation itself takes place.

The reaction is carried out under atmospheric pressure and attemperatures ranging from 30 to 50C.

The diacetyl dimer is prepared in the aldolic form according to themethod of O. Diels, W. M. Blanchardt, H. Heyden [Berichte, 47, 2359].

The dimer is used in excess with respect to tetrazonium sulfate. Ingeneral, a molar ratio of 6-7 l is employed.

Tetra-azotation of aromatic diamines is obtained by the action ofnitrosyl-sulfuric acid on the diamines. In order for the reaction tooccur satisfactorily, it is advisable to add the aromatic diamine veryslowly and under vigorous stirring to the sulfuric solution containingthe stoichiometric quantity of nitrosylsulfuric acid while maintainingtemperature constant at around C. The reaction ends upon totaldissolution of the diamine.

By slowly pouring the thus obtained sulfuric solution into acetonecooled to l5C, the tetrazonium sulfate of the diamine used is obtainedby precipitation of the solution. By operating in this manner, it ispossible to obtain the tetrazonium sulfate of aromatic amines with goodyields. The products according to the invention can be easily purifiedby sublimation.

The following examples are given to better illustrate the invention, andare not intended to be limiting.

EXAMPLE 1' 24 g of concentrated H 80 are fed into a 100 cc Erlenmeyerflask provided with a magnetic stirrer and cooled with ice. 2.76 g .ofNaNO are added very slowly, in such a manner that no yellow fumes areproduced.-The mixture is then heated slowly under stirring to atemperature ofC so as to have an almost complete solution. The whole isallowed to cool to room temperature. 15.5 g of 78% H 80 are added. TheNa SO formed starting from the sulfuric solution of nitrosylsulfuricacid is filtered, 1.9 g of p-phenylendiamine are added very slowly understirring, keeping the temperature between 20 25C. The sulfuric solutionobtained at the end of the reaction is poured slowly into acetone cooledto 15C. The tetrazonium sulfate precipitates and is purified with coldacetone and filtered.

5.5 g of product are obtained.

2.7 g of tetrazonium sulfate are mixed with 10 g of the diacetyl dimerin the aldolic form in a small 50 cc flask provided with a' mechanicalstirrer and a cooler. The mixture is heated under stirring to 35 40C forsixhours. At the end of the run, the whole is washed 1 with ether untilthe diacetyl dimer disappears. The solid residue is boiled with acetone.3.4 g of crude, doublysalified product having the formula:

CH3 1+. a. l. 2 2

C H N S calculated 36.05 3.86 12.01 13.73 found 37.65 4.05 1.84 12.37

The salt, suspended in H O, loses H 80 and gives the final product. 1.9g of crude product are obtained. The product is purified by sublimation.

The elementary analysis of the sublimated product gives the followingvalues (for C H N O C H N calculated 62.61 5.22 20.73 found 61.95 5.1720.29

The product does not show a melting point at 320C. The IR. spectrum isin accordance with the pyrazolone structure. The M.W. (determined bymass spectography) is 270.

EXAMPLE 2 5.4 g of m-phenylendiamine tetrazonium sulfate prepared as inExample 1 are mixed with 20 g of the diacetyl dimer in the aldolic formin a small 50 cc flask provided with a mechanical stirrer and a cooler.The

3 4 mixture is heated under stirring to 35 40C for six hours. At the endof the reaction, ether is added to which comprises reacting solidparaor, respectively, remove the diacctyl. The residue is dispersed inwater meta-phenylendiamine tetrazomum sulphate with diand the reactionproduct precipitates. The filtered solid etyl dim r in ldolic form, in am lar r i of fr m is dried and purified with acetone. 2.9 g of crudeprod- 5 to :1, r about ix r under m p ri p uct are obtained. sure and ata temperature of 30C to 50C, washing the For further purification, theproduct is dissolved in ea tion product comprising the salt of the 1N,1151'- 10% NaOH, heated under reflux for 3 hours, and re- P ormeta-phenylenbis y -py precipitated with 10% HCL'The product may be bli-3-0ne) thus obtained with ether to remove unreacted mated. The analysisof the sublimated product gives the diacetyl dimer and dispersing the inWater to libel" following values (for CI'4HHN4OZ); ate H S0 and recoverthe IN, IN -paraor meta-phenylenbis (5-methyl-4-pyrazolin-3-one).

2. The compound C H N calculated 62.2l 5.22 20.73 found 62.47 5.49 20.28O

The Sublimated product does not show a melting c \c point at 320C. Thel. R. spectrum is in accordance with the pyrazolone structure. The M. W.(determined 0 O by mass spectrography) is 270.

What we claim is: The compound 1. A process for preparing 1N, iN'-paraormetaphenylenbis (5-methyl-4-pyraaolin-3-ones) having the formula CH-C 3Afi- O \c u c cn g N c CH N 3 \e ll

1. A PROCESS FOR PREPARING 1N, 1N''-PARA-OR META-PHENYLENBIS(5-METHYL-4-PYRAZOLIN-3-ONES) HAVING THE FORMULA
 2. The compound
 3. Thecompound